JP2005331930A - In-finder display device and camera having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an in-finder display device which is reduced in cost and can be miniaturized. <P>SOLUTION: The in-finder display device includes an optical flat plate 6, arranged about a position where an image is formed by a photographic optical system 2 and having a prism section a pentagonal roof prism 7 receiving the light from the pentagonal roof prism 7; an eyepiece unit 10 for guiding the light from the pentagonal roof prism 7 to an observer; an LED unit 9 as a light source; and an illumination optical system 8 for guiding the light from the LED unit 9 to the prism section. The light from the LED unit 9 reflected off the prism section of the optical flat plate 6 is guided via the pentagonal roof prism 7 and the eyepiece unit 10 to the observer. The prism section disposed at the optical flat plate 6 has two prism faces, and the ridgeline formed by the two prism faces is nonparallel to the plane orthogonal to an optical axis of the photographic optical system 2. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an in-finder display device suitable for displaying shooting information in a finder of a single-lens reflex camera, for example.

  2. Description of the Related Art Conventionally, a so-called superimpose display function for displaying shooting information superimposed on a subject image in a finder of a single-lens reflex camera is known. As a display device having such a function, for example, as described in Patent Document 1, a plurality of light emitting elements, a deflection unit corresponding to each of the plurality of light emitting elements, and a reflecting surface are included in the viewfinder screen. There are some which display a plurality of focus detection points in a superimposed manner.

  FIG. 9 is a diagram illustrating a configuration of the in-finder display device disclosed in Patent Document 1. In FIG.

  In FIG. 9, reference numeral 91 denotes a quick return mirror for guiding light from a photographing optical system (not shown) to the viewfinder optical system. The light from the subject reflected by the quick return mirror 91 forms an image on the focusing screen 92. The subject image formed on the focusing screen 92 passes through an optical member 93 for superimposing display and a pentaprism 94 and an eyepiece 95 for making the subject image formed on the focusing screen 92 an erect image. To the eyes of the photographer. Reference numeral 96 denotes an LED (light emitting diode) for superimposing display. Light from the LED 96 is guided to the optical member 93 through the illumination optical system 97 and the pentaprism 94. Here, as shown in FIG. 11, the optical member 93 has a prism portion 111 formed on the surface on the focusing screen 92 side, and passes through the illumination optical system 97 and the pentaprism 94 by the prism surface 111a and the prism surface 111b. The reflected light is reflected and guided to the photographer's eyes.

  FIG. 10 is a view of FIG. 9 as viewed obliquely from above. Reference numerals 103a to 103e denote LEDs, which respectively correspond to the focus detection frames 121a to 121e in the viewfinder field shown in FIG. The focus detection frames 121a to 121e are illuminated by turning on the LEDs 103a to 103e, respectively. Further, reference numeral 102 in FIG. 10 denotes an illumination optical system, which corresponds to 97 in FIG. Here, the illumination optical system 102 has a surface having power on the side facing the pentaprism 101, and the surface having the power corresponds to a region corresponding to the focus detection frames 121a and 121b, and 121c. Are divided into three areas, that is, the area corresponding to 121d and 121e. The three divided areas play a role of guiding light from the LEDs 103a to 103e to the photographer's pupils in the longitudinal direction of FIG.

According to the configuration as described above, it is possible to superimpose and display a plurality of focus detection points arranged at the center and the periphery of the screen.
Japanese Patent Application Laid-Open No. 08-043913

  However, in the configuration described in Patent Document 1, when the number of focus detection points to be superimposed is increased, an illumination optical system for guiding light from the light source to the photographer's pupil, or There is a problem that the surface having power provided in the illumination optical system must be increased, resulting in an increase in size and cost of the camera.

  An object of the present invention is to provide an in-finder display device that can be reduced in size at low cost in view of the above-described problems of the prior art.

  An exemplary intra-viewfinder display device of the present invention is disposed at or near the position where an image is formed by an objective unit, an optical member having a prism portion, an image reversing unit on which light from the optical member is incident, An eyepiece unit that guides light from the image reversing unit to an observer, a light source, and an illumination unit that guides light from the light source to the prism unit, and the light from the light source reflected by the prism unit It is guided to the observer through the eyepiece unit. The prism portion provided in the optical member has two prism surfaces, and the ridge line formed by the two prism surfaces is not parallel to a plane orthogonal to the optical axis of the objective unit.

  ADVANTAGE OF THE INVENTION According to this invention, the display apparatus in a finder which can be reduced in size at low cost can be provided.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing a configuration of an optical system of a single-lens reflex camera provided with an in-finder display device according to an embodiment of the present invention.

  In the figure, reference numeral 1 denotes a lens barrel including a photographing optical system (objective unit) 2, and 3 denotes a camera body. Here, the lens barrel 1 and the camera body 3 can be attached and detached. Reference numeral 4 denotes a quick return mirror for guiding light from a subject passing through the photographing optical system 2 to the finder optical system. Although not shown, a silver salt film and a solid-state imaging device (CCD or CMOS sensor) are arranged behind the quick return mirror 4 (direction in which light from the photographing optical system 1 goes straight). The quick return mirror 4 switches between the photographing optical path and the viewfinder optical path by rotating in conjunction with the release of the camera. The light reflected upward by the quick return mirror 4 forms an image on the upper surface of the focusing screen 5. Here, a Fresnel surface is formed on the lower surface of the focusing screen 5.

  Above the focusing screen 5, an optical flat plate 6 for displaying in the finder screen and a penta roof prism for guiding the subject image formed on the focusing screen 5 to the pupil of the photographer (observer) as an erect image. An image reversing unit) 7 is provided. The penta roof prism 7 includes an entrance surface 7c, an exit surface 7a, and a plurality of reflection surfaces. Further, an optical surface 7b for guiding illumination light to the optical flat plate 6 for performing display in the viewfinder screen is formed above the exit surface 7a of the penta roof prism 7. The optical surfaces 7b and 7a make an angle θ.

  The subject image formed on the focusing screen 5 by the photographing optical system 2 is inverted to an erect image by the penta roof prism 7 and guided to the photographer by the eyepiece lens (eyepiece unit) 10. A viewfinder optical system including the focusing screen 5, the optical flat plate 6, the penta roof prism 7, and the eyepiece 10 is configured so that a photographer can observe a rectangular field corresponding to the film surface or the imaging surface of the solid-state imaging device. Yes. In FIG. 1, the left-right direction corresponds to the short-side direction of the observation visual field (up-down direction of the visual field), and the direction perpendicular to the paper surface corresponds to the long-side direction of the observation visual field (horizontal direction of the visual field).

  Furthermore, an illumination optical system (illumination unit) 8 and an LED unit (light source) 9 are provided above the optical surface 7b. As shown in FIG. 2, the LED unit 9 has a configuration in which a plurality of LED arrays 21 are arranged on one chip, and each LED array is paired with a focus detection point of a focus detection device (not shown). It has become.

  Here, the angle θ formed by the optical surfaces 7b and 7a is preferably set within a range of 110 degrees <θ <165 degrees. When the lower limit of this range is exceeded, the reflection area provided in the roof portion of the penta roof prism 7 must be made small in order to obtain a sufficient range for transmitting the light beam from the illumination optical system 8. As a result, the subject image or information such as the shutter speed at the time of shooting displayed below the subject image is easily vignetted. If the upper limit is exceeded, the effective area of the optical surface 7b cannot be taken sufficiently.

  The light emitted from the LED unit 9 is transmitted through the illumination optical system 8 and the optical surfaces 7b and 7c of the pentaprism 7, and is optically flat from the short side direction of the observation field within the plane including the optical axis of the photographing optical system 1. Illuminate 6 diagonally. The light reflected by the prism portion corresponding to the focus detection frame provided on the lower surface of the optical flat plate 6 is guided to the photographer's pupil through the pentaprism 7 and the eyepiece 10 together with the subject image.

  Here, as shown in FIG. 3, the focus detection frame 12 is formed on the optical flat plate 6 by a fine prism at a position corresponding to the arrangement of the LED array 11 of the LED unit 9. 4A is an enlarged view of the focus detection frame 12a located at the center of the screen (field of view) in FIG. 3, and FIG. 4B is an enlarged view of the focus detection frame 12b located in the periphery in the horizontal direction of the screen. FIG. Here, the fine prism portion constituting the focus detection frame is a roof prism as shown in FIG. Then, as shown in FIG. 5, the ridge line 13 of each prism portion is inclined when projected onto a cross section in the short side direction of the field of view (a plane including the optical axis of the photographing optical system 1, the paper surface in FIG. 1). The optical flat plate 6 is not parallel to the surface (a plane perpendicular to the optical axis).

  In this way, the ridge line of the prism part constituting the focus detection frame is inclined with respect to a plane perpendicular to the optical axis, corresponding to the direction in which the illumination light is obliquely incident, thereby making complex illumination as in the past. Even without adopting an optical system, the reflected light from the prism portion can be guided to the photographer. For this reason, the illumination optical system 8 for superimpose display may be configured with a single lens as in this embodiment, and superimpose display can be performed with a simple configuration.

  Further, at the focus detection point at the center of the screen and the focus detection points directly above and below it, as shown in FIG. 4A, the edge line of the roof prism is parallel to the vertical direction of the viewfinder field. On the other hand, at the peripheral distance measuring points, as shown in FIG. 4B, the ridge lines of the roof prism are arranged at a certain angle α with respect to the vertical and horizontal directions of the viewfinder field. Here, the angle α is an intersection line between the optical flat plate 6 and the plane defined by the center of the exit pupil of the illumination optical system 8, the center of each focus detection point around the screen, and the center of the entrance pupil of the eyepiece 10. The angle is determined by the direction.

  As described above, even if the illumination optical system 8 is constituted by a single lens by tilting the ridge 13 of the prism constituting the focus detection frame 12 with respect to the surface on which the optical flat plate 6 is formed, the LED unit 9 Can be guided to the photographer's eyes. Further, by configuring the prism constituting the focus detection frame 12 with a roof prism, it becomes possible to efficiently guide the light from the LED unit 9 to the pupil of the photographer, so that a brighter viewfinder display is performed. It becomes possible.

  In the present embodiment, the focusing screen 5 and the optical flat plate 6 are configured as separate members, but the focusing screen 5 and the optical flat plate 6 may be configured as a single member. That is, a focus detection frame in which the prism portion described in the present embodiment is formed may be provided on the focusing screen arranged at the imaging position of the photographing optical system.

  Next, a second embodiment of the present invention will be described.

  The configuration as a camera is the same as that of the first embodiment, and the configuration is as shown in FIG. The difference between the present embodiment and the first embodiment is that the shape of the prism constituting the focus detection frame on the optical flat plate 6 is different.

  FIG. 6 is a diagram showing the arrangement of the focus detection frames on the optical flat plate 6. Each focus detection frame is formed by a fine prism portion as in the first embodiment. FIG. 7A is an enlarged view of the focus detection frame 14a located at the center of the screen (field of view) in FIG. 6, and FIG. 7B is an enlargement of the focus detection frame 14b located at the periphery in the horizontal direction of the screen. FIG.

  Here, the ridgeline 13 of each prism part is not parallel to the surface formed by the optical flat plate 6 as shown in FIG. However, this embodiment differs from the first embodiment in that each prism portion is not constituted by a roof prism, and the angle formed by the two surfaces of the prism is about 100 degrees. As a result, about half of the light from the illumination optical system 8 is guided to the photographer's pupil, and the amount of light guided to the photographer's pupil is about half that of the case where the roof prism is used. However, when the roof prism is used, as shown in FIG. 4B, the ridge line of the prism portion is made non-parallel to the surface of the optical flat plate 6 and the focus detection frame at the peripheral portion of the screen is made into a perfect square shape. It is difficult to. On the other hand, by releasing from the restriction of the roof prism, the focus detection frame at the peripheral portion of the screen can be made into a perfect square shape as shown in FIG. For this reason, this embodiment is better than the first embodiment in the sense of unity of the visibility of the focus detection frame.

  Next, a third embodiment of the present invention will be described.

  The configuration as a camera is the same as that of the first and second embodiments, and the configuration is as shown in FIG. In the third embodiment, as shown in FIG. 8, in addition to the focus detection frame 15a, an index 15b indicating the photometric range is formed on the optical flat plate 6, which is different from the first and second embodiments. .

  Thus, by forming the focus detection frame and the index indicating the photometric range on the same member, it is possible to reduce the manufacturing cost. Further, as compared with the case where the focus detection frame and the index indicating the photometry range are formed as separate members, the positional relationship between the focus detection frame and the index indicating the photometry range does not shift.

It is a figure explaining Example 1 of the present invention. It is a figure of the LED unit used for the display in a finder. FIG. 3 is a diagram illustrating an arrangement of focus detection frames on the optical flat plate according to the first embodiment. FIG. 3 is an enlarged view of a focus detection frame on the optical flat plate of Example 1. It is a side view of the prism which forms a focus detection frame. FIG. 10 is a diagram illustrating an arrangement of focus detection frames on the optical flat plate according to the second embodiment. 6 is an enlarged view of a focus detection frame on an optical flat plate according to Embodiment 2. FIG. It is a figure showing the arrangement | positioning of the parameter | index which shows the focus detection frame and optical measurement range on the optical flat plate of Example 3. FIG. It is a figure showing the example of the conventional display apparatus in a finder. FIG. 10 is a perspective view of the conventional example shown in FIG. 9. FIG. 10 is an enlarged view of the optical member 93 shown in FIG. 9. It is a figure showing the finder visual field of the prior art example shown in FIG. It is a perspective view of a prism part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lens barrel 2 Shooting optical system 3 Camera body 4 Quick return mirror 5 Focusing plate 6 Optical flat plate 7 Penta roof prism 8 Illumination optical system 9 LED unit 10 Eyepiece

Claims (10)

An optical member having a prism portion disposed at or near the position where an image is formed by the objective unit, an image inverting unit on which light from the optical member is incident, and light from the image inverting unit is guided to an observer An eyepiece unit, a light source, and an illumination unit that guides light from the light source to the prism unit, and the light from the light source reflected by the prism unit is observed through the image inversion unit and the eyepiece unit. A display device in the finder led to the user,
The in-finder display device, wherein the prism unit has two prism surfaces, and a ridge formed by the two prism surfaces is not parallel to a plane orthogonal to the optical axis of the objective unit.   The in-finder display device according to claim 1, wherein the light source and the illumination unit are arranged so as to illuminate the prism portion obliquely within a plane including an optical axis of the objective unit.   The in-finder display device according to claim 2, wherein a ridge line of the prism portion projected onto a plane including the optical axis of the objective unit is non-parallel to a plane orthogonal to the optical axis of the objective unit.   4. The finder according to claim 1, wherein the image inversion unit is a penta roof prism, and the penta roof prism has an optical surface that transmits light from the illumination unit between the roof surface and the exit surface. Display device. An angle θ formed by an optical surface that transmits light from the illumination unit provided in the penta roof prism and an exit surface of the penta roof prism is:
110 ° <θ <165 °
The in-finder display device according to claim 4, wherein the following condition is satisfied. An optical member that is disposed at or near the position where an image is formed by the objective unit and that has a focus detection frame, an image reversing unit on which light from the optical member is incident, and light from the image reversing member to the viewer An eyepiece unit for guiding, a light source, and an illumination unit for guiding the light from the light source to the focus detection frame, and the light from the light source reflected by the focus detection frame passes through the image inversion unit and the eyepiece unit. A display device in the finder guided to the observer,
The focus detection frame is formed by a plurality of prism portions each having two prism surfaces, and a ridge line formed by the two prism surfaces of each prism portion is relative to a plane orthogonal to the optical axis of the objective unit. In-finder display device characterized by being non-parallel.   The in-finder display device according to claim 6, wherein the light source and the illumination unit are arranged to illuminate the focus detection frame obliquely within a plane including the optical axis of the objective unit.   The optical member has a plurality of focus detection frames, each focus detection frame is formed by the plurality of prism portions, and a focus located within a plane including the optical axis of the objective unit among the plurality of focus detection frames. The ridge line of the prism portion forming the detection frame is non-parallel to a plane orthogonal to the optical axis of the objective unit within a plane including the optical axis of the objective unit. Display device in the viewfinder.   The optical member has a plurality of focus detection frames, each focus detection frame is formed by the plurality of prism portions, and a focus located outside the plane including the optical axis of the objective unit among the plurality of focus detection frames. The in-finder display device according to any one of claims 6 to 8, wherein a ridge line of a prism portion forming a detection frame is not parallel to a plane including an optical axis of the objective unit.   An in-finder display device comprising: a mirror that separates a finder optical path and a photographing optical path; and the in-finder display device according to claim 1 disposed in the finder optical path separated by the mirror.

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